Sludge discharging centrifugal separators



April 16, 1963 P.$TE1NACKER ETAL 3,085,743

SLUDGE DISCHARGING CENTRIFUGAL SEPARATORS Filed Jan. 16. 1959 12 H r'5.3L I80. 29 INVENTORS PETER STEINACKER v HEINRICH HEMFORT as 30ATTORNEYS 3,085,743 Patented Apr. 16, 1963 3,085,743 SLUDGE DISCHARGINGCENTRIFUGAL SEPARATORS Peter Steinacker and Heinrich Hemfort, Oelde,Westphalia, Germany, assignors to Westphalia Separator AG., Oelde,Westphalia, Germany, a German corporation Filed Jan. 16, 1959, Ser. No.787,309 Claims priority, application Germany Feb. 11, 1954 Claims. (Cl.233-) This invention relates to improvements in sludge dischargingcentrifugal separators, and is a continuation-inpart of copending US.application, Serial No. 433,708, filed June 1, 1954, now abandoned.

Centrifugal separators which have bowls from which accumulated sludgemay be periodically discharged are known. These separators may have acentrifugal bowl with peripheral sludge discharge openings which may beopened and closed by an axially movable sleeve valve. The sleeve valvemay be hydraulically operated in one or both directions.

For this purpose the bowl may have a bottom insert which forms thebottom surface of the bowl interior. This bottom insert has a lowersurface positioned in spaced relationship to the upper surface of thebottom portion of the bowl casing. The sleeve valve has an inwardlyextending flange or plate which is positioned in this space and dividesthe same into an upper opening chamber and a lower closing chamber. Thecontrol is effected by introducing a control liquid such as water intothe opening chamber above the flange, or into the closure chamber belowthe flange. Due to the centrifugal force of the rotating bowl, theliquid acts under pressure in these chambers. There is, thus, producedin one of the two chambers an excess pressure which effects the downwardor upward movement of the sleeve valve whereby the sludge dischargeopenings are exposed or closed.

Various embodiments of such control systems are known. In someembodiments both chambers are filled independently of each other withcontrol liquid through channels or holes while in other embodiments, thechambers have a common feed channel.

In the case of centrifugal separators of the latter type, the openingchamber may have small discharge conduits at its outer periphery throughwhich the control liquid may leave the chamber. In order to effectopening of the sleeve valve for the discharge of the sludge, morecontrol liquid is introduced into the opening chamber than can bedischarged through its peripheral conduits. As a result, the liquidbuilds up in the opening chamber and a centrifugal pressure head isformed which forces the inwardly extending flange and the sleeve valvedownward and displaces the control liquid present in the closurechamber. After the sludge has been discharged, the control liquidintroduced into the opening chamber is throttled or interrupted so thatthe same may discharge through the peripheral conduits. The controlliquid at the same time is allowed to build up in the closure chamber sothat the pressure of the centrifugal head in this chamber exceeds thatin the opening chamber and the sleeve valve is moved upwardly to closethe sludge discharge openings. In general, water is used as the controlliquid.

In order to effect a dependable closure of the sleeve valve, acontinuing small feed of water must be maintained after the refilling ofthe closure chamber particularly when centrifuging at high temperaturein order to equalize any losses occurring by evaporation, leakage or thelike. In this connection passage of the control water from the closurechamber into the opening chamber is permissible to a certain extentinasmuch as this water again discharges out of the peripheral conduits.If this continuous feed, however, exceeds the discharge rate throughthese conduits, the control water collects in the opening chamber andwill force the sleeve valve downward and hold it in the open position.If, on the other hand, the continuous admission to the closure chamberis less than the amount lost by evaporation, etc., the amount of controlwater in the closure chamber will gradually decrease to below the amountrequired to maintain the sleeve valve closed.

A further disadvantage of conventional sludge discharge centrifugalseparators is the fact that the opening of the sludge discharge outletsoften takes place too slowly. This occurs because the mass in theclosure chamber is somewhat inwardly displaced upon moving the sleevevalve to opened position, increasing the working surface area of saidsleeve valve as it so moves. Further more, an increase incountcrpressure results in the closure chamber acting to retard theopening of said valve, necessitating additional filling of the openingchamber and an increase in the filling time. These actions delay rapidopening of conventional sludge discharge outlets. As a consequence, therinsing liquid fed to the drum for removing the sludge may break throughthe cake of solids formed along the separator wall during sludgeseparation, thereby causing any advantageous pressure build-up to belost. Under these conditions, the solids may be only partially expelledso that strong imbalances of the rotating drum may occur.

It is an object of the present invention, therefore, to overcome theabove disadvantages of variations in rate of feed of the control liquidto the opening chamber and slowly opening sludge discharge outlets.

It is another object of the invention to provide a sludge dischargecentrifugal separator construction wherein the closure chamber has asmaller radially extending working surface area and a correspondinglygreater annular or longitudinally extending working surface area withrespect to the axis of rotation of the separator.

It is a further object of the invention to provide a closure chamberconstruction whereby the opening and closing of the sludge dischargeopenings of a centrifugal separator may take place rapidly, particularlyin moving the sleeve valve into opened position.

Other and further objects of the present invention will become apparentfrom a study of the within specification and accompanying drawing inwhich:

FIG. 1 shows an embodiment of a centrifuge in accordance with theinvention, with the sleeve valve in the closed position, and

FIG. 2 shows the embodiment shown in FIG. 1 with the sleeve valve in theopen position.

The centrifugal separator, in accordance with the invention, has aclosure chamber developed as a storage chamber which will not force allof the material used for effecting the closing actuation therefrom evenwhen the sleeve valve is in the open position. At least a predeterminedportion of the mass which is flowable or deformable under centrifugalforce is permanently contained in the closure chamber. This mass, forexample, may consist of a liquid which does not evaporate even atincreased temperature or a plastic or elastic mass.

The closure chamber should be outwardly sealed, but may he provided withan opening in its end portion a predetermined distance from the axis ofrotation of the centrifuge through which the centrifugally deformableclosure material may be introduced and from which the excess of thismaterial over the predetermined amount desired may be discharged uponthe first sludge removal.

Since at least a predetermined amount of the centrifugally deformablemass used for the closing actuation of the valve is substantiallypermanently positioned in the closure chamber and is merely deformedoutwardly upon closing actuation and flattened out upon openingactuation, no feed channel is required into the closure chamber, and theclosure chamber no longer need be in communication with the openingchamber.

The inwardly extending flange which is connected to the sleeve valvepreferably extends to adjacent the hub of the centrifugal bowl so thatthe opening liquid may exert a force on a larger area than in previouslyknown embodiments. The closure material, furthermore, acts in the openposition of the sleeve valve on a larger area than in the closedposition. Thus, this material will exert a larger force at the beginningof the upward movement of the valve where it is needed to overcome thestarting friction.

When an elastic material as, for example, rubber is used as the closurematerial, a preliminary stressing of this material in the form it takeswhen the sleeve valve is closed may be effected so that the initialforce exerted on the sleeve valve in its movement from the open to theclosed position is further increased to overcome the starting frictionwhich, as is well known, is greater than the sliding friction.

It has been found also in accordance with the present invention that byproviding an increased distance, in a longitudinal direction withrespect to the axis of rotation, between the flange connected to thelower portion of the sleeve valve and a portion of the bottom of thebowl casing, as by an annular extension in said bowl casing bottom, whenthe sleeve valve is in closed position the working surface area of thedeformable mass in the closure chamber during rotation is only slightlyincreased radially inwardly upon movement of the sleeve valve to theopened position. Moreover, in accordance with the invention, theeffective surface area on which the closing deformable mass may exertits force is considerably diminished in the peripheral portion of theclosure chamber farthest from the axis of rotation, that is, where theforce of said mass is greatest, upon moving the sleeve valve to openedposition, while the remaining effective surface area as aforesaid isonly slightly increased in a direction towards the axis because of suchannular e'xtension. Consequently, upon movement of the sleeve valve intoopened position, as when liquid is conducted to the opening chamber inconventional manner, the counteracting force of the deformable orflowable mass in the closure chamber is considerably less than thatexerted in conventional separators, permitting speedy movement of thesleeve valve from closed to opened position. Conversely, it will be seenthat upon dis-continuing liquid to the opening chamber, due to thecentrifugal force acting on the deformable or flowablc mass, the sleevevalve will be forced toward the closed position enabling more and moreof said mass to occupy the peripheral portion of the closure chamber,whereby said valve will be quickly and completely forced to closedposition.

Constructions in accordance with the present invention, such as thoseabove described, therefore, favorably provide for the etlicient andrapid opening and closing of the sludge discharge openings, utilizingthe centrifugal force of the separator to advantage. Specifically, thecake of solids deposited in the drum during separation of the sludgefrom the accompanying liquid will be completely discharged from the drumunder the pressure of the rinsing liquid, eliminating any possibleimbalancing of the drum, since the sleeve valve is quickly moved intoopened position. Conversely, the sleeve valve is quickly moved intoclosed position, since the deformable mass passes immediately into thespace formed in the periph eral portion of the closure chamber, wherethe force of said mass is greatest, upon initial movement of the sleevevalve toward the closed position. Because of such great force the sleevevalve is caused to complete its movement to the closed position rapidly,without noticeable displacement of the deformable mass toward theperipheral portion of the closure chamber.

In the preferred embodiment of the invention, wherein a llowable mass isused in the closure chamber, one or more limiting exit tubes or channelsconnecting said closure chamber with the outside are provided whereby agiven quantity of said mass will always be present in said chamber.These tubes project into said chamber a predetermined distance, or arepositioned at a point in the chamber wall a given distance from theaxis, so that a sufficient quantity of tlowable mass will always bepresent in said closure chamber.

Among the deformable or flowable mass materials which may be used inaccordance with the invention are any flowable plastic and elasticmaterials, any deformable plastic and elastic materials, water, andwater-based deformable or llowable materials, all of said materialsbeing capable of deforming or flowing under centrifugal force andpreferably being liquid.

The term llowable mass or flowable material as used in the appendedclaims is meant to embrace and include both flowable and deformablemasses and materials of the type immediately hereinabove set forth.

It will be seen, therefore, that the present invention advantageouslyprovides a closure chamber in centrifugal separators having a widenedannular space portion into which the deformable or llowable mass may bedirected during movement of the sleeve valve into opened position withonly a slight increase in working surface area in a radially inwarddirection. Furthermore, the invention provides such a closure chamberhaving a varying volume peripheral portion in which the working surfacearea decreases during movement of the sleeve valve to opened positioncorrespondingly decreasing the force of the flowable or deformable massthereat, and increases during movement. of said valve to closed positioncorrespondingly increasing the force of said mass thereat. Consequently,the closure chamber construction of the invention enables the sleevevalve to respond rapidly to open and close the sludge dischargeopenings, due to the immediate decrease in the force of the fiowable ordeformable mass upon moving said sleeve valve to opened position and theimmediate increase in the force of said mass upon moving said sleevevalve to closed position, respectively.

The invention may be further described in greater detail with referenceto the embodiment shown in the accompanying drawings.

The centrifugal bowl'is composed of the lower casing part 1 and theupper casing part or cover part 2, which are connected to each other bymeans of the locking ring 3. The bowl is mounted for rotation with thespindle 28 in the conventional manner. The bowl casing is provided withperipheral sludge discharge openings or ports 20. A sleeve valve 21 isaxially movable within the bowl between a position shown in FIG. 1 ofthe drawing in which its upper edge contacts the gasket 22 and seals thedischarge openings Ztl and a lower position shown in FIG. 2 of thedrawing in which its upper edge is in spaced relationship to the gasket22 opening the sludge discharge openings 20.

A bottom insert member 6 defines the lower surface of the bowl interiorand is spaced from the bottom 5 of the bowl casing to define a freespace therebetween. The distributor 4 which extends axially upward tothe central portion of the bowl is formed as an integral portion of thebottom insert member 6. This distributor distributes material introducedinto the centrifuge through the conduit 19 in the bowl through theconduit 23.

The bottom insert member 6 has an outer annular guide surface 8 whichacts as a sliding guide for the sleeve valve 21.

A flange 10 is connected to the lower portion of the sleeve valve 21 asan integral part thereof and moves therewith. This flange 10 extendsinwardly and divides the free space between the member 6 and bottom 5into an upper opening chamber 12 and a lower closure chamber 11. Theinner end of the flange terminates as a guide surface 9, which slides incontact with the hub of the centrifugal drum.

The lower closure chamber 11 is formed as an outwardly confined storagespace which is dimensioned for maintaining at least a given quantity ofdeformable or fiowable material such as liquid, plastic or elasticmaterial therein at any position of movement of the sleeve valve 21 andthe flange 10.

A control liquid such as water may be introduced into the upper openingchamber 12 through the conduits 16 and 17. Liquid may be removed fromthis chamber by centrifugal action through the outlet conduit 13 in thesleeve valve 21 and the port 14.

In operation, the centrifugal bowl is rotated with the spindle 28 in theconventional manner. The material to be treated is introduced throughthe inlet pipe 19 and passes through the distributor 4 and conduit 23into the interior of the bowl which contains the conventional discinserts 24. The lighter liquid passes inwardly over the disc insert andis discharged over the overflow lip 25. The heavier liquid is forced bythe centrifugal force outwardly and passes upward and is discharged overthe overflow lip 26. Solid materials or the like, designated as sludge,accumulate at the peripheral portion 7 of the bowl interior.

Before the separator is placed in operation, a closure liquid having ahigh boiling point or a plastic or elastic material is introduced intothe closure chamber 11 in amount at least suflicient to fill the chamberto the level 15 indicated in FIG. 1 of the drawing during thecentrifuging with the sleeve valve 21 in the closed position. Thedeformable material is forced outwardly by the centrifugal action andforces the flange 10 and the sleeve valve 21 upward in the closedposition.

in order to open the sludge discharge openings, water or similar controlliquid is introduced through the pipe 16 and conduit 17 into the openingchamber 12. The amount of water introduced should exceed the amountwhich is forced out by the centrifugal action through the opening 13 andport 14. A centrifugal head of water thus builds up in the openingchamber 12. When this head builds up so that a pressure is formed whichexceeds the pressure in the closure chamber 11, the flange 10 and sleevevalve 21 are forced downwardly to the position indicated in FIG. 2 ofthe drawing. The centrifugal pressure within the bowl can then force thesludge out through the annular space between the upper edge of the valve21 and the gasket 22 and through the discharge openings 20. When sludgedischarge has been completed, the water passing through 16 is shut oiland the water passes out of the chamber 12 through the opening 13 andport 14. The pressure caused by the centrifugal force acting on thedeformable or flowable mass in the chamber 11 then forces the flange 10and sleeve valve 21 upwardly into the closed position and maintains thesame in that position until water is again introduced into the openingchamber 12.

Any excess of the deformable closure material which has been introducedinto the closure chamber 11, as, for example, upon assembly thereof maydischarge through the opening 18 or 180 upon the first opening actuationof sleeve valve 21. When the closure chamber 12 is filled with water, itis difficult to prevent small amounts of Water from leaking out alongthe guide surface 9. In order to seal the closure chamber 11 from thisleakage, a small ring chamber 29 is provided below the guide surface 9.Any water leaking through the guide surface will therefore accumulate inthis ring chamber. A drain conduit 27 is provided from the ring chamberthrough which the water may pass out.

As the closure chamber 11 is formed as a storage space, and is closedoff to prevent entrance of control liquid from the opening chamber, thedeformable mass may remain as a substantially permanent part of theapparatus within the closure chamber without subsequent additions, etc.The opening and closing are completely actuated by passing the controlliquid into the opening chamber and by allowing the same to flow outtherefrom.

More specifically, closure chamber 11 is provided with a widened annularspace 30, which receives a substantial portion of the deformable orfiowable mass which is displaced from the peripheral portion of chamber11 upon movement of sleeve valve 21 to opened position as shown in FIG.2. A shift in the level of said mass from that indicated at 15 in H6. 1to that indicated at 15:: in FIG. 2 therefore takes place. Because ofthe location of pro jection tube 18 in the bottom surface of bowl casingS of FIG. 1, or channel tube 180 in sleeve valve 21 communicating withport 14 of P16. 2, with respect to the desired level of deformable orflowable mass disposed in closure chamber 11, said mass will not passout of said chamber under centrifugal action except to the limit defined by tube 18 or 18a.

Due to the considerably decreased working surface area in the peripheralportion of closure chamber 11 and the comparatively insignificantincreased working surface area in the annular extension space 30, uponinitial movement of the sleeve valve 21 toward opened position whenliquid is passed to opening chamber 12, the sleeve valve 21 will quicklymove to fully opened position as shown in FIG. 2. Conversely, due to theconsiderably increased working surface area in the peripheral portion ofclosure chamber 11 and the comparatively insignificant decreased workingsurface area in the annular extension space 30, upon initial movement ofthe sleeve valve 21 toward closed position when liquid is no longerpassed to opening chamber 12, the sleeve valve 21 will quickly move tofully closed position as shown in FIG. 1.

In operation, during rotation the level of the flowablc material isshown radially outwardly at level 15, the flowable material occupyingthe peripheral portion of the closing chamber 11 when no control liquidis passed through conduits 16 and 17 to the opening chamber 12. Thelevel of the flowable material is determined radiullyinwardly by thepresence of tube 18:: which allows excess flowable material to pass offfrom closing chamber 11 through tube 18a and port 14. It will bespecifically noted that the peripheral bottom surface of flange 10 andthe adjacent peripheral surface of the bottom 5 of the casing togetherdefine an area of flow-able material working surface radially inwardlyto the level 15. As may be seen from FIG. 2, when control liquid passesthrough conduits 16 and 17 to opening chamber 12, centrifugal action ofthe control liquid dammed up within opening chamber 12 due to thecomparatively small flow cross-section of outlet conduit 13 willdownwardly urge the flange 18 so as to open the ports 2!] for dischargeof collected sludge in the conventional manner. The level of theflowable macrial within the closing chamber 11 will therefore beradially inwardly displaced from the level 15 to the level 15a. This isdue to the fact that the volume of the closing chamber 11 is decreased.At this time the peripheral bottom surface of flange 10 will engage theadjacent peripheral surface of the bottom 5 whereby the area of flowablematerial working surface will be decreased by an extent equal to thearea of abutment between said peripheral bottom surface of flange 10 andadjacent peripheral surface of bottom 5. However, due to the increasedaxial dimensions of the annular extension space 30 with respect to theperipheral portion of closing chamber 11, the portion of Working surfaceincreased by the radially inward displacement of the flowable materialfrom the level 15 to the level will only insignificantly compensate forthe loss of working surface due to the peripheral abutting engagement ofthe bottom surface of flange 10 and the corresponding surface of bottom5 of the casing. Thus, the movement of flange 10 from closing positionto opening position will decrease the volume of closing chamber 11, atthe same time decreasing the effective flowable material working surfacearea within closing chamber l1. Accordingly, since a decreased Workingsurface area is involved, the flange 10 will immediately respond tocontrol liquid passed to opening chamber 12 and rapidly and abruptlyopen the discharge ports for the effective discharge of sludge from thedrum. On the other hand, upon cessation of the feeding of control liquidto opening chamber 12, as the flange 10 moves upwardly, an effectiveincrease in flowable material worll'ing surface area becomes availabledue to the parting of the abutting portions of flange 10 and bottom 5 ofthe casing, whereby rapid and abrupt upward movement of the flange willoccur so as to close ports 20 in the desired manner. Since the force ofthe flowable material is greater in the peripheral portion than in theannular space 30, the abrupt movement of the flange 10 will occur witheven greater effectiveness.

While the specification and accompanying drawings have been set forthfor the purpose of illustration, it will be understood that variouschanges and modifications may be made without departing from the spiritand scope of the invention which is to be limited only by the scope ofthe appended claims.

We claim:

1. In a centrifugal separator having a centrifugal bowl with peripheralsludge discharge openings and an axially movable sleeve valve, movablebetween a position opening and a position closing said sludge dischargeopenings, the improvement which comprises an insert member defining anend surface of the bowl interior and positioned to define a free spacebetween it and the adjacent wall portion of the how], a flange connectedto said sleeve valve for movement therewith extending inwardly withinsaid free space dividing the same into an opening chamber and a closurechamber, means for introducing liquid into said opening chamber duringcentrifugal operation to move said sleeve valve to opening position andmeans for the removal of liquid from said opening chamber, said closurechamber containing flowable material therewithin and having means forsealing said closure chamber against the flow and overflow of saidmaterial therefrom into said opening chamber and for sealing saidclosure chamber against the complete outward flow of said materialtherefrom both at standstill and under centrifugal action whereby agiven mass of a flowable closure material will be maintained thereinboth at standstill and during operation and in any position of movementof said sleeve valve for closing actuation of said sleeve valve, saidclosure chamber defining between the flange and the adjacent wallportion of the bowl an outwardly confined storage space having, whensaid sleeve valve is in closing position, a radially wide and axiallynarrow dimensioned peripheral zone completely occupied by said flowablematerial during centrifugal operation and a radially narrow and axiallywide dimensioned annular zone inwardly with respect to said peripheralzone only partially occupied by said flowable material duringcentrifugal operation, whereas when said sleeve valve moves to openingposition, both the radially wide and axially narrow dimensions of saidperipheral zone substantially decrease and the flow-able materialtherein is forced therefrom into said annular Zone while the axiallywide dimension of said annular zone only slightly decreases and theradially narrow dimension of said annular zone remains substantiallyconstant.

2. Improvement according to claim 1 wherein said flowable material is aplastic material.

3. Improvement according to claim 1 wherein said flowable material is anelastic material.

4. Improvement according to claim 3 wherein said elastic material isrubber.

5. In a centrifugal separator having a centrifugal bowl with peripheralsludge discharge openings and an axially movable sleeve valve, movablebetween a position opening and a position closing said sludge dischargeopenings,

the improvement which comprises an insert member defining an end surfaceof the bowl interior and positioned to define a free space between itand the adjacent wall portion of the bowl, a flange connected to saidsleeve valve for movement therewith extending inwardly within said freespace dividing the same into an upper opening chamber and a lowerclosure chamber, said closure chami361 defining by means of said flangeand the bowl an outwardly confined adjustable volume storage spacedimensioned thereby for the maintaining of a predetermined quantity offlowable material therein undzr centrifugal action and at standstill inany position of movement of said sleeve valve and in turn said flange,said flange substantially completely sealing said closure chamber fromflow communication with said opening chamber, an elastic flowablematerial positioned in said closure chamber and means for introducingliquid into said opening chamber during centrifugal operation to movesaid sleeve valve to opening position and means for the removal ofliquid from said opening chamber, said adjustable volume storage spacehaving, when said sleeve valve is in closing position, a radially wideand axially narrow dimensioned peripheral zone completely occupied bysaid flowable material during centrifugal operation and a radiallynarrow and axially wide dimensioned annular zone inwardly disposed withrespect to said peripheral zone only partially occupied by said flowablematerial during centrifugal operation, whereas when said sleeve valvemoves to opening position, both the radially wide and axially narrowdimensions of said peripheral zone substantially decrease and the flou/able material therein in forced therefrom into aid annular zone whilethe axially wide dimension of said annular zone only slightly decreasesand the radially narrow dimension of said annular zone remainssubstantially constant.

6. In a centrifugal separator having a centrifugal bowl with peripheralsludge discharge openings and an axially movable sleeve valve, movablebetween a position opening and a position closing said sludge dischargeopenings, the improvement which comprises an insert member defining anend surface of the bowl interior and positioned to define a free spacebetween it and the adjacent wall portion of the bowl, a flange connectedto said sleeve valve for movement therewith extending inwardly withinsaid free space dividing the same into an opening chamber and a closurechamber, said closure chamber defining by means of said flange and thebowl an outwardly confined storage space adjustable in volume independence upon the movement of said flange, containing a flowablematerial therewithin and being peripherally and annularly dimensionedthereby for permanently maintaining at least a predetermined amount ofsaid flowable material therein under centrifugal action and atstandstill in any position of movement of said sleeve valve and in turnsaid flange, said flange substantially completely sealing said closurechamber from flow communication with said opening chamber and definingwith the bowl interior a closure chamber radially outward annularperipheral portion having a substantially decreased flowable materialworking surface area in opening position of movement of said flange withsaid sleeve valve and a substantially increased flowable materialworking surface area in closing position of movement of said flange,said flange further defining with said bowl interior a closure chamberradially inward annular axial portion having a slightly increasedflowable material working surface area in opening position of movementof said flange with said sleeve valve and a slightly decreased flowablematerial working surface area in closing position of movement of saidflange, and means for introducing liquid into and for the removal ofliquid from said open chamber, whereby upon actuation of said sleevevalve to opened position by introducing liquid into said openingchamber, the working surface area of said flowable material against saidflange at the peripheral portion of said closure chamber willsubstantially decrease and the working surface area of said flowablematerial against said flange at the annular portion of said closurechamber will only slightly increase, while upon actuation of said sleevevalve to closed position by the removal of liquid from said openingchamber, the working surface area of said material against said flangeat said peripheral portion will substantially increase and the workingsurface area of said material against said flange at said annularportion will only slightly decrease, enabling said sleeve valve to moverapidly to both the opened and closed positions without increasing anddecreasing the amount of flowable material within said closed chamberupon such actuation.

7. Improvement according to claim 1 wherein an opening communicatingwith the exterior of said separator is provided in the upwardly limitingwall of the closure chamber a predetermined radial distance from theperiphery of said closure chamber and axially above a predeterminedlevel of said flowable material in said closure chamber when saidseparator is at standstill, whereby complete outward fiow of saidfiowable closure material will be prevented and a given mass of saidmaterial will be maintained therein in any said position of movement ofsaid sleeve valve.

8. Improvement according to claim 1 wherein a tubular extensioncommunicating with the exterior of said separator projects apredetermined distance into said closure chamber a predetermineddistance from the periphery of said closure chamber and axially above apredetermined level of said fiowable material in said closure chamberwhen said separator is at standstill, whereby complete outward fiow ofsaid fiowable closure material will be prevented and a given mass ofsaid material will be maintained therein in any said position ofmovement of said sleeve valve.

9. Improvement according to claim 6 wherein an opening communicatingwith the exterior of said separator is provided in the upwardly limitingflange wall of the closure chamber a predetermined radial distance fromthe periphery of said closure chamber and axially above a predeterminedlevel of said fiowable material in said closure chamber when saidseparator is at standstill, whereby complete outward flow of saidfiowable closure material will be prevented and a given mass of saidmaterial will be maintained therein in any said position of movement ofsaid sleeve valve.

10. Improvement according to claim 6 wherein a tubular extensioncommunicating with the exterior of said separator projects apredetermined distance into said closure chamber a predetermineddistance from the periphery of said closure chamber and axially above apredetermined level of said fiowable material in said closure chamberwhen said separator is at standstill, whereby complete outward flow 0tsaid flowable closure material will be prevented and a given mass ofsaid material will be maintained therein in any said position ofmovement of said sleeve valve.

References Cited in the tile of this patent UNITED STATES PATENTS878,591 Sonnenfeld et al. Apr. 18, 1905 957,347 Kennedy May 10, 19102,103,822 Perry Dec. 28, 1937 FOREIGN PATENTS 122,937 Sweden Oct. 5,1948 616,442 Great Britain Jan. 21, 1949

1. IN A CENTRIFUGAL SEPARATOR HAVING A CENTRIFUGAL BOWL WITH PERIPHERALSLUDGE DISCHARGE OPENINGS AND AN AXIALLY MOVABLE SLEEVE VALVE, MOVABLEBETWEEN A POSITION OPENING AND A POSITION CLOSING SAID SLUDGE DISCHARGEOPENINGS, THE IMPROVEMENT WHICH COMPRISES AN INSERT MEMBER DEFINING ANEND SURFACE OF THE BOWL INTERIOR AND POSITIONED TO DEFINE A FREE SPACEBETWEEN IT AND THE ADJACENT WALL PORTION OF THE BOWL, A FLANGE CONNECTEDTO SAID SLEEVE VALVE FOR MOVEMENT THEREWITH EXTENDING INWARDLY WITHINSAID FREE SPACE DIVIDING THE SAME INTO AN OPENING CHAMBER AND A CLOSURECHAMBER, MEANS FOR INTRODUCING LIQUID INTO SAID OPENING CHAMBER DURINGCENTRIFUGAL OPERATION TO MOVE SAID SLEEVE VALVE TO OPENING POSITION ANDMEANS FOR THE REMOVAL OF LIQUID FROM SAID OPENING CHAMBER, SAID CLOSURECHAMBER CONTAINING FLOWABLE MATERIAL THEREWITHIN AND HAVING MEANS FORSEALING SAID CLOSURE CHAMBER AGAINST THE FLOW AND OVERFLOW OF SAIDMATERIAL THEREFROM INTO SAID OPENING CHAMBER AND FOR SEALING SAIDCLOSURE CHAMBER AGAINST THE COMPLETE OUTWARD FLOW OF SAID MATERIALTHEREFROM BOTH AT STANDSTILL AND UNDER CENTRIFUGAL ACTION WHEREBY AGIVEN MASS OF A FLOWABLE CLOSURE MATERIAL WILL BE MAINTAINED THEREINBOTH AT STANDSTILL AND DURING OPERATION AND IN ANY POSITION OF MOVEMENTOF SAID SLEEVE VALVE FOR CLOSING ACTUATION OF SAID SLEEVE VALVE, SAIDCLOSURE CHAMBER DEFINING BETWEEN THE FLANGE AND THE ADJACENT WALLPORTION OF THE BOWL AN OUTWARDLY CONFINED STORAGE SPACE HAVING, WHENSAID SLEEVE VALVE IS IN CLOSING POSITION, A RADIALLY WIDE AND AXIALLYNARROW DIMENSIONED PERIPHERAL ZONE COMPLETELY OCCUPIED BY SAID FLOWABLEMATERIAL DURING CENTRIFUGAL OPERATION